Home
Back
Barlow's Formula:
| From: | To: |
Barlow's Formula estimates surface runoff from rainfall using a runoff coefficient that varies based on catchment characteristics and seasons. It provides a simple method for calculating runoff volume in hydrological studies.
The calculator uses Barlow's Formula:
Where:
Explanation: The formula multiplies the rainfall amount by a coefficient that represents the proportion of rainfall that becomes surface runoff, accounting for factors like soil type, slope, and land cover.
Details: Accurate runoff estimation is crucial for water resource management, flood prediction, irrigation planning, and environmental impact assessments in catchment areas.
Tips: Enter Barlow's Runoff Coefficient (between 0 and 1) and Rainfall in centimeters. The coefficient varies based on catchment characteristics - higher values indicate more impervious surfaces.
Q1: What are typical values for Barlow's Runoff Coefficient?
A: Coefficient values range from 0.1-0.2 for forested areas, 0.2-0.4 for agricultural land, 0.4-0.6 for suburban areas, and 0.7-0.9 for urban areas with impervious surfaces.
Q2: How does season affect the runoff coefficient?
A: The coefficient is typically higher during wet seasons when soils are saturated and lower during dry seasons when infiltration capacity is greater.
Q3: What are the limitations of Barlow's Formula?
A: The formula is simplistic and doesn't account for rainfall intensity, duration, antecedent moisture conditions, or complex catchment topography.
Q4: How is runoff usually measured?
A: Runoff is typically measured as seasonal or annual totals, often using stream gauges or calculated from water balance equations.
Q5: Can this formula be used for stormwater management?
A: While useful for preliminary estimates, more sophisticated models are recommended for detailed stormwater management and flood control design.